Dr. A. Braun on the Vegetable IndividuaL 347 



tween essential and unessential branches, it cannot, when ana- 

 lysed, establish a distinction which will enable us to decide 

 upon their importance as individuals ; for even those branches 

 which appear unessential, in relation to the formation of flowers 

 and fruit, may yet be essential to the plant in other relations : 

 as when they appear as characteristic elements of the vegetable 

 structure, or when they play any important part in the ceconomy 

 of the plant, as I have shown in eootenso elsewhere*. Nay, 

 more ; one and the same branch, as to whose nature there seems 

 to be no doubt, may appear either as essential or as unessential, 

 according to circumstances. When those branches which con- 

 duct the structure to a higher stage of its development appear 

 in great numbers, on a principal axis, as e. g. in indefinite 

 racemose or spicate inflorescence, the lateral branchlets appearing 

 as flowers are then indeed, generally speaking, necessary to the 

 plant^s full completion of the series of formations, and in this 

 sense essential ; but their number is immaterial as regards this 

 completion ; and this the plant itself shows in producing either 

 a larger or a smaller number of them j sometimes the number is 

 reduced to onef. Therefore, properly speaking, only one lateral 

 flower is essential ; and we may arbitrarily consider any one of 

 the number to be this essential one. Hence each of them may 

 be regarded indift'erently as essential or unessential. This is 

 not the case in those racemes and spikes which possess a ter- 

 minal flower, as is the case in many CampanulacecBy e. g. in Cam- 

 panula rapunculoides. Here, all the lateral flowers are unessen- 

 tial ; yet if the terminal flower is cut off", the lateral branchlets 

 which bear the flowers at once become essential. Such a change 

 is not always artificial, for it often happens naturally, as there 

 are plants in which the terminal flower may be either present or 

 absent. Agrimonia Eupatoria and Campanula rapunculoides 

 are examples of this variability f . 



* Verjiingung, p. 41 et seq, ; .I:-.,:^f iKrUllh ^jUiiuict 



t E.gf. not unfrequently in the raceme of Lathyrus odoratus. 

 X Agrimonia Eupatoria bears usually one spike without any terminal 

 flower ; in weak specimens, a terminal flower not unfrequently makes its 

 appearance, which opens before the upper lateral flowers. This has been 

 observed by Wydler (Bot. Zeit. 1844, p. 642). In Campanula rapuncu- 

 loides the case is just the contrary : its looser spikes are usually terminated 

 with a flower, while denser ones end in a coma of bracteal leaves, without 

 any terminal flower. Dictamnus resembles Agrimonia ; while Triglochin 

 (especially Tr. maritimum) on the other hand imitates Campanula. Even 

 in plants in which the essentiality of the lateral position of the flower is 

 expressed by their zygomorphic development, terminal flowers make their 

 appearance in some cases ; they then resemble Pelorice. This is the case 

 in Linaria, Orobanche, and a Digitalis purpurea monstrosa (described by 

 Vrohk, Flora, 1844, No. 1), which propagates by seeds, and is now widely 

 disseminated in our gardens. 



